Those are what I have now - they get freakin' hot. Ive read reviews about the heat spreaders coming loose and I can see it on mine - the way the clips hold the heat spreaders on, it pulls away near the pins and pulls together near the top, so about half the chip has a good connection with the thermal pad. I took the clips off so hopefully the spreaders stay on all the way, but that seems like bad design to me. And that's running stock clocks, I cant imagine if I was overclocking like mad.
Anyways, it should be easier to overclock 2x2gb sticks than 4x1gb sticks, correct?